import sys
import pygame
from source.gui.bullet import Bullet
from source.gui.alien import Alien
from time import sleep


def check_keydown_events(event, ai_settings, screen, ship, bullets,music,stats):
    """响应按键"""
    if event.key == pygame.K_RIGHT:
        # 向右移动飞船
        ship.moving_right = True
    if event.key == pygame.K_LEFT:
        ship.moving_left = True
    if event.key == pygame.K_SPACE:
        # 创建一颗子弹，并加入到编制bullets中
        if len(bullets) <= ai_settings.bullets_allowed:
            new_bullet = Bullet(ai_settings, screen, ship)
            bullets.add(new_bullet)
            #射击的音效
            music.hit_music(stats)


def check_keyup_events(event, ship):
    """响应松开"""
    if event.key == pygame.K_RIGHT:
        ship.moving_right = False
    if event.key == pygame.K_LEFT:
        ship.moving_left = False


def check_events(ai_settings, stats,score, play_button, screen, ship, aliens, bullets, music):
    """响应按键和鼠标事件"""
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            #储存最高分
            stats.write_highsore()
            sys.exit()
        elif event.type == pygame.KEYDOWN:
            check_keydown_events(event, ai_settings, screen, ship, bullets,music,stats)

        elif event.type == pygame.KEYUP:
            check_keyup_events(event, ship)
        elif event.type == pygame.MOUSEBUTTONDOWN:
            mouse_x, mouse_y = pygame.mouse.get_pos()
            check_play_button(ai_settings, screen, stats,score, play_button, ship, aliens, bullets, mouse_x, mouse_y, music)


def check_play_button(ai_settings, screen, stats,score, play_button, ship, aliens, bullets, mouse_x, mouse_y, music):
    """在玩家点击play按钮时开始新的游戏"""
    # collidepoint函数时判断鼠标点击的位置是否在play按钮内
    button_clicked = play_button.rect.collidepoint(mouse_x, mouse_y)
    if button_clicked and not stats.game_active:
        # 重置游戏设置
        ai_settings.initialize_dynamic_settings()
        # 播放背景音乐
        music.start_music()
        # 隐藏光标
        pygame.mouse.set_visible(False)
        # 重置游戏统计信息
        stats.reset_stats()
        stats.game_active = True
        #重置记分牌图像
        score.prep_score()
        score.prep_high_score()
        score.prep_level()
        score.prep_ships()
        # 清空外星人列表和子弹列表
        aliens.empty()
        bullets.empty()

        # 创建一群新的外星人，并让飞船居中
        create_fleet(ai_settings, screen, ship, aliens)
        ship.center_ship()


def update_screen(ai_settings, screen, stats, score, ship, aliens, bullets, play_button):
    """更新屏幕上的图像，并切换到新屏幕"""
    # 每次循环都重新绘制屏幕
    screen.fill(ai_settings.bg_color)
    # 在飞船和外星人后面重新绘制子弹
    for bullet in bullets.sprites():
        bullet.draw_bullet()
    ship.blitme()
    # 创建外星人群
    aliens.draw(screen)

    # 显示得分
    score.show_score()
    # 如果游戏处于非活动状态，就绘制play按钮
    if not stats.game_active:
        play_button.draw_buttion()
        if stats.game_over:
            play_button.draw_game_over_button()
    # 让最近绘制的屏幕可见
    pygame.display.flip()


def update_bullets(ai_settings, screen, stats, score, ship, aliens, bullets,music):
    """更新子弹的位置，并删除消失的子弹"""
    # 更新子弹的位置
    bullets.update()
    # 删除已经消失的子弹
    for bullet in bullets.copy():
        if bullet.rect.bottom < 0:
            bullets.remove(bullet)
    # print("当前子弹的数量为："+str(len(bullets)))
    check_bullet_alien_collisions(ai_settings, screen, stats, score, ship, aliens, bullets,music)


def create_fleet(ai_settings, screen, ship, aliens):
    """创建外星人群"""
    # 创建一个外星人，并计算一行可容纳多少个外星人
    # 外星人间距为外星人宽度
    alien = Alien(ai_settings, screen)
    alien_aliens_x = get_number_aliens_x(ai_settings, alien.rect.width)
    number_rows = get_number_rows(ai_settings, ship.rect.height, alien.rect.height)
    # 创建多行外星人
    for row_number in range(number_rows):
        # 创建一行外星人
        for alien_number in range(alien_aliens_x):
            # 创建一个外星人并加入到当前行
            create_alien(ai_settings, screen, aliens, alien_number, row_number)


def get_number_aliens_x(ai_settings, alien_width):
    """计算每行可容纳多少个外星人"""
    avaible_space_x = ai_settings.screen_width - 2 * alien_width
    number_aliens_x = int(avaible_space_x / (2 * alien_width))
    return number_aliens_x


def create_alien(ai_settings, screen, aliens, alien_number, row_number):
    # 创建一个外星人并加入到当前行
    alien = Alien(ai_settings, screen)
    alien_width = alien.rect.width
    alien.x = alien_width + 2 * alien_width * alien_number
    alien.rect.x = alien.x
    alien.rect.y = alien.rect.height + 2 * alien.rect.height * row_number
    aliens.add(alien)


def get_number_rows(ai_settings, ship_height, alien_height):
    """计算屏幕可容纳多少行外星人"""
    available_space_y = ai_settings.screen_height - (3 * alien_height) - ship_height
    number_rows = int(available_space_y / (2 * alien_height))
    return number_rows


def update_aliens(ai_settings, screen,stats,score,ship,aliens,bullets):
    """更新外星人群中所有外星人的位置"""
    check_fleet_edges(ai_settings, aliens)
    # 会自动调用alien类中的update方法
    aliens.update()
    # 检测外星人和飞船之间的碰撞
    if pygame.sprite.spritecollideany(ship,aliens):
        ship_hit(ai_settings, screen,stats,score,ship,aliens,bullets)
    # 检测是否有外星人到达屏幕的底端
    check_aliens_bottom(ai_settings, screen,stats,score,ship,aliens,bullets)


def check_aliens_bottom(ai_settings, screen, stats, score, ship, aliens, bullets):
    """检查是否有外星人抵达屏幕底端"""
    screen_rect=screen.get_rect()
    for alien in aliens.sprites():
        if alien.rect.bottom >=screen_rect.bottom:
            #像外星人被飞船撞到一样处理
            ship_hit(ai_settings, screen, stats, score, ship, aliens, bullets)


def check_fleet_edges(ai_settings, aliens):
    """有外星人到达边缘时采取相应的措施"""
    for alien in aliens.sprites():
        if alien.check_edges():
            change_fleet_direction(ai_settings, aliens)
            break


def change_fleet_direction(ai_settings, aliens):
    """将整个外星人下移，并改变其方向"""
    for alien in aliens.sprites():
        alien.rect.y += ai_settings.fleet_drop_speed
    ai_settings.fleet_direction *= -1


def ship_hit(ai_settings, screen,stats,score,ship,aliens,bullets):
    """响应飞船被外星人撞到"""
    if stats.ships_left > 0:
        stats.ships_left -= 1
        #更新记分牌
        score.prep_ships()
    else:
        #存储最高分
        stats.write_highsore()
        stats.game_active = False
        stats.game_over=True
        pygame.mouse.set_visible(True)

    # Empty the list of aliens and bullets.
    aliens.empty()
    bullets.empty()

    # Create a new fleet, and center the ship.
    create_fleet(ai_settings, screen, ship, aliens)
    ship.center_ship()

    # Pause.
    sleep(0.5)


def check_bullet_alien_collisions(ai_settings, screen, stats, score, ship, aliens, bullets,music):
    """检查子弹，外星人的状态"""
    # 检查是否有子弹击中外星人，击中了就删除对应的子弹和外星人
    collisions = pygame.sprite.groupcollide(bullets, aliens, True, True)
    if collisions:
        for hit_aliens in collisions.values():
            stats.score += ai_settings.alien_points * len(hit_aliens)
            score.prep_score()
            music.blast_music()
        check_high_score(stats,score)

    """检查外星人的数量，没有在创建"""
    if len(aliens) == 0:
        # 删除现有的子弹，加快游戏节奏，并创建一群新的外星人
        bullets.empty()
        ai_settings.increase_speed()
        # 提升等级
        stats.level +=1
        # 更新等级图像
        score.prep_level()
        music.level_music()
        # 创建外星人群
        create_fleet(ai_settings, screen, ship, aliens)


def check_high_score(stats,score):
    """检查是否诞生了最高得分"""
    if stats.score > stats.high_score:
        stats.high_score=stats.score
        score.prep_high_score()